As shown in Japanese Patent Disclosure No. 57-77759, the inventor proposed a method and an apparatus for exchanging an expansion joint used for long period of time by providing each iron bar with a tensely weakened portion and embedding the iron bars and elongated inflatable flat vessels of metallic material in a reinforced concrete for fixing an expansion joint. In exchange, pressurized liquid is supplied into the vessels to cause them to inflate by the internal pressurized liquid so that the iron bars break at the weakened portion to separate and elevate a part of the reinforced concrete from a base concrete for easy removal of the reinforced concrete. However, this method is defective and almost unpractical in that it involves demolishing noise when the reinforced concrete is broken and crushed by drills or breakers operated for long hours. Also, in some cases, a base concrete beneath the reinforced concrete may unnecessarily or accidentally be broken by excessive crushing operation of breakers, requiring an additional work to repair the broken base concrete.
An inflatable flat vessel is formed by pressing a metallic pipe into a flat shape with bent side edges of so larger radius and thickness in cross section as to avoid metal fatigue that may occur at the bent edges by pressing. In another aspect, a recent and general method for demolishing concrete constructions utilizes a diamond cutter that has a rotatable circular blade with tips of diamond powder attached to an outer periphery of the blade. The rotating blade may cut a reinforced concrete to form a slit of thin width, for example, less than approximately four (4) millimeters width. However, cutters of this kind have not been used in removing a reinforced concrete for fixing expansion joints
The present invention provides a method and an apparatus for easily removing a part of concrete construction such as a reinforced concrete for fixing expansion joints in a shorter period of time without giving rise to noise pollution, avoiding damage to a base concrete beneath the reinforced concrete by excessive demolition.